WARM PITCHED ROOF

I think of doing a loft conversion on my bungalow but the rafters are quite thin and head height is a little tight so as I need to re-roof my slate roof I thought I would go for a warm roof construction to help with the head height issue. My problem arises as I am only in a semi detachted I wondered 1 whether the planning will allow it and 2 how I would construct the joint between me and my neighbours house. They re-roofed there house last year but didn't overlap the slates and put some thing underneath them which my help me?? But not sure how to go about the joint section.
Thanks for any help you can give

A warm roof construction will add a minimum of 125mm to the existing height, what with insulation and counterbattens and all.

You will lose at best 65mm from below the rafters, also remember that the new floor will reduce head height another 150-200mm. So is this viable? Bungalow roofs are normally feasible to allow a loft conversion though

It may be worth considering a large dormer to get more useful headroom and remove the sloping ceiling

Planning would resist letting you raise the roof above next doors.

But would it be cost effective to pay for, or contribute to the cost of insulating and raising your neighbours roof too?

For the junction, you just form a timber upstand and lead flash to nexts doors roof